This invention relates to a tone signal generating device, and more particularly to a tone signal generating device which is capable of controlling, by means of a simple structure, tone color of a tone to be generated, in an extensive and diversified manner with increased flexibility.
In Japanese Patent Publication No. Sho 59-19354, for example, a tone signal generating device is disclosed which generates a tone signal utilizing a noise signal produced from a signal generating source. More specifically, a tone signal generating device, a noise signal having, at an uniform level, frequency components of virtually all band areas. The noise signal is passed through a filter that is composed of delay loop circuitry of a comb-like frequency characteristic having a plurality of resonance peaks, so that a signal of a specific frequency band corresponding to a depressed key on a keyboard etc. is selectively extracted. The extracted signal is then generated as a tone signal which has a pitch corresponding to the depressed key.
However, because the prior art tone signal generating device merely generates a noise signal regular or fixed frequency characteristics by means of an impulse generator or white noise generator or the like and then passes the regular noise signal through the comb filter, it can only control tone color of a tone to be generated, with a limited flexibility to a limited extent (it only relies on the comb filter characteristics). To solve such a problem, it may be effective to alter the construction of the filter circuit and also variably establish the filter coefficients. But, this approach is not satisfactory in that it requires a large scale circuitry and and also requires complex control for establishing filter coefficients.
Therefore, it is an object of the present invention to provided a tone signal generating device which is capable of controlling, by means of a simple structure, tone color of a tone to be generated in an extensive and diversified manner with increased flexibility.